WESTERN SIBERIAN PLAIN (West Siberian Lowland), one of largest plains the globe. It is located in the northern part of Asia, in Russia and Kazakhstan. The area is over 3 million km2, including 2.6 million km2 in Russia. The length from west to east is from 900 km (in the north) to 2000 (in the south), from north to south up to 2500 km. In the north it is washed by the Arctic Ocean; in the west it borders on the Urals, in the south - on the Turgai plateau and the Kazakh hills, in the southeast - on the mountains of Southern Siberia, in the east - along the valley of the Yenisei River with the Central Siberian plateau.

Relief. It is a low accumulative plain with a rather uniform relief, various forms permafrost(common up to 59° northern latitude), increased bogging and ancient and modern salt accumulation developed in the south in loose rocks and soils. Heights of about 150 m predominate. In the north, in the area of ​​\u200b\u200bdistribution of marine accumulative and moraine plains, the general flatness of the territory is disturbed by moraine gently sloping and hilly-sloping (North-Sosvinskaya, Lyulimvor, Verkhne-, Srednetazovskaya, etc.) elevations 200-300 m high, the southern border of which runs about 61-62 ° north latitude; they are horseshoe-shaped covered from the south by flat-topped elevations Belogorsky Continent, Siberian Uvaly, etc. In the northern part, permafrost exogenous processes(thermal erosion, heaving of soils, solifluction), on sandy surfaces - deflation, on swamps - peat accumulation. There are numerous ravines on the plains of the Yamal and Gydansky peninsulas and on the moraine uplands. To the south, the area of ​​moraine relief is adjoined by flat lacustrine-alluvial lowlands, the lowest (height 40-80 m) and swampy of which are Kondinskaya and Sredneobskaya. The area not covered by the Quaternary glaciation ( south of the line Ivdel - Ishim - Novosibirsk - Tomsk - Krasnoyarsk), is a weakly dissected denudation plain, rising (up to 250 m) to the Urals. In the interfluve of the Tobol and the Irtysh, there is an inclined, in places with ridges, lacustrine-alluvial Ishim plain (120-220 m) with a thin cover of loess-like loams and loess occurring on salt-bearing clays. It is adjacent to the alluvial Baraba lowland and Kulunda plain, where the processes of deflation and modern salt accumulation are developing. In the foothills of the Altai - ridge-ridged Priobskoe plateau (height up to 317 m - the highest point West Siberian Plain) and the Chulym Plain. O geological structure and minerals, see the article West Siberian Platform, with which the West Siberian Plain is geostructurally connected.

Climate. prevails continental climate. Winter in the polar latitudes is severe and lasts up to 8 months (almost 3 months lasts polar night), average January temperatures from -23 to -30 °С; in the central part, winter lasts up to 7 months, average January temperatures are from -20 to -22 °С; in the south, where the influence of the Asian anticyclone intensifies, winters are shorter at the same temperatures (up to 5-6 months). Minimum temperature air -56 °С. In summer, the western transport of the Atlantic air masses with intrusions in the north of cold air from the Arctic, and in the south - dry warm air masses from Kazakhstan and Central Asia. In the north, summer is short, cool and humid with a polar day, in the central part it is moderately warm and humid, in the south it is arid and dry, with dry winds and dust storms. The average July temperature rises from 5°C in the Far North to 21-22°C in the south. The duration of the growing season in the south is 175-180 days. Atmospheric precipitation falls mainly in summer. The wettest (400-550 mm per year) are the Kondinskaya and Sredneobskaya lowlands. To the north and south, the annual precipitation gradually decreases to 250 mm.

surface waters. There are more than 2,000 rivers in the West Siberian Plain belonging to the basin of the Arctic Ocean. Their total flow is about 1200 km 3 of water per year; up to 80% annual runoff occurs in spring and summer. The largest rivers are the Ob, Yenisei, Irtysh, Taz and their tributaries. The feeding of the rivers is mixed (snow and rain), the spring flood is extended, the low water is long summer-autumn and winter. The ice cover on the rivers lasts up to 8 months in the north, up to 5 in the south. major rivers navigable, are important rafting and transport routes and, in addition, have large reserves hydropower resources. total area lakes more than 100 thousand km2. The largest lakes are located in the south - Chany, Ubinskoe, Kulunda. In the north - lakes of thermokarst and moraine-glacial origin. There are many small lakes in suffusion depressions (less than 1 km 2): on the Tobol-Irtysh interfluve - more than 1500, on the Baraba lowland - 2500, including fresh, salty and bitter-salty; there are self-sustaining lakes.

Landscape types. The uniformity of the relief of the vast West Siberian Plain determines a clearly expressed latitudinal zonality landscapes, although, compared with the East European Plain, the natural zones here are shifted to the north. On the Yamal, Tazovsky and Gydansky peninsulas, in conditions of continuous permafrost, landscapes of arctic and subarctic tundra with moss, lichen and shrubs (dwarf birch, willow, alder) cover on gleyzems, peat-gleyzems, peat-podburs and soddy soils were formed. Polygonal mineral grass-hypnum bogs are widespread. The share of primary landscapes is extremely insignificant. To the south, tundra landscapes and swamps (mostly flat-hummocky) are combined with larch and spruce-larch woodlands on podzolic-gley and peat-podzolic-gley soils, forming a narrow forest-tundra zone, transitional to the forest (forest-bog) zone temperate zone, represented by subzones of the northern, middle and southern taiga. Swampiness is common to all subzones: over 50% of the area of ​​the northern taiga, about 70% - middle, about 50% - southern. The northern taiga is characterized by flat and large-hummocky raised bogs, the middle taiga is characterized by ridge-hollow and ridge-lake bogs, the southern taiga is characterized by ridge-hollow, pine-shrub-sphagnum, transitional sedge-sphagnum and low-lying tree-sedge bogs. The largest marsh massif is the Vasyugan Plain. The forest complexes of different subzones, formed on the slopes with varying degrees drainage. Northern taiga forest complexes on permafrost are represented by sparse and low-growing pine, pine-spruce and spruce-fir forests on gley-podzolic and podzolic-gley soils. The indigenous landscapes of the northern taiga occupy 11% of the area of ​​the West Siberian Plain. Common to the forest landscapes of the middle and southern taiga is the wide distribution of lichen and shrub-phagnum pine forests on sandy and sandy loamy illuvial-ferruginous and illuvial-humus podzols. On loams in the middle taiga, spruce-cedar forests with larch and birch forests are developed on podzolic, podzolic-gley, peat-podzolic-gley and gley peat-podzols. In the subzone of the southern taiga, on loams, there are spruce-fir small-grass forests and birch forests with aspen on sod-podzolic and sod-podzolic-gley (including those with a second humus horizon) and peat-podzolic-gley soils. Primary landscapes in the middle taiga occupy 6% of the area of ​​the West Siberian Plain, in the southern - 4%. The subtaiga zone is represented by park pine, birch and birch-aspen forests on gray, gray gley and soddy-podzolic soils (including those with a second humus horizon) in combination with steppe meadows on cryptogley chernozems, solonetsous in places. Indigenous forest and meadow landscapes are practically not preserved. Boggy forests turn into lowland sedge-hypnum (with ryams) and sedge-reed bogs (about 40% of the zone). For the forest-steppe landscapes of sloping plains with loess-like and loess covers on salt-bearing tertiary clays, birch and aspen-birch groves on gray soils and malts are typical in combination with forb-grass steppe meadows on leached and cryptogley chernozems, to the south - with meadow steppes on ordinary chernozems, in places solonetzic and saline. On the sands pine forests. Up to 20% of the zone is occupied by eutrophic reed-sedge bogs. In the steppe zone, the primary landscapes have not been preserved; in the past, these were forb-feather grass steppe meadows on ordinary and southern chernozems, saline in places, and in drier southern areas- fescue-feather grass steppes on chestnut and cryptogley soils, gley solonetzes and solonchaks.

Environmental problems and protected natural areas. In areas of oil production due to pipeline breaks, water and soil are polluted with oil and oil products. In forestry areas - overcutting, swamping, the spread of silkworms, fires. In agrolandscapes, there is an acute problem of lack of fresh water, secondary salinization of soils, destruction of soil structure and loss of soil fertility during plowing, drought and dust storms. In the north - degradation of reindeer pastures, in particular due to overgrazing, which leads to a sharp reduction in their biodiversity. No less important is the problem of preserving hunting grounds and habitats of fauna.

To study and protect typical and rare natural landscapes Numerous reserves, national and natural parks have been created. Among largest reserves: in the tundra - the Gydansky reserve, in the northern taiga - the Verkhnetazovsky reserve, in the middle taiga - the Yugansky reserve, etc. national park- Priishimskiye Bory. Natural parks are also organized: in the tundra - Deer streams, in the northern taiga - Numto, Siberian Uvaly, in the middle taiga - Kondinsky lakes, in the forest-steppe - Bird's harbor.

Lit.: Trofimov V. T. Patterns of spatial variability of engineering-geological conditions of the West Siberian plate. M., 1977; Gvozdetsky N. A., Mikhailov N. I. Physical geography of the USSR: Asian part. 4th ed. M., 1987; ground cover and land resources Russian Federation. M., 2001.

The West Siberian Lowland covers an area of ​​about 3 million square kilometers. It covers 1/7 of the entire territory of Russia. The width of the plain varies. In the northern part it is about 800 km, and in the southern part it reaches 1900 km.

Areas

The West Siberian lowland is considered the most densely populated part of Siberia. On its territory there are several large areas, these are such as Omsk, Tyumen and Kurgan, as well as Novosibirsk and Tomsk. The greatest development of the lowland is noted in its southern part.

Climatic conditions

The climate in the lowland is dominated by continental, rather severe. Because of long distance In the West Siberian Plain, from north to south, there are significant differences in the climate of the southern part from the northern one. Big role in the making weather conditions the proximity of the Arctic Ocean plays, as well as the fact that on the plain there are no obstacles to the movement of air masses from north to south and their mixing.

In the cold season, an area appears over the southern part of the lowland. high blood pressure, while in the north it decreases. Cyclones form at the boundary of air masses. Because of this, in regions located on the coast, the weather is very unstable in winter. can reach 40 meters per second. Winter throughout the territory of such a plain as the West Siberian Lowland is characterized by stable sub-zero temperatures, the minimum can reach -52 o C. Spring comes late and is cold and dry, warming occurs only in May.

In the warm season, the situation is reversed. Pressure rises over the Arctic Ocean, which causes northerly winds to blow throughout the summer. But they are pretty weak. July is considered the hottest time within the boundaries of the plain, called the West Siberian Lowland. During this period, in its northern part, the maximum temperature reaches 21 o C, and in the south - 40 o C. Such high marks in the south are quite explained by the fact that the border with Kazakhstan passes here and Central Asia. This is where warm air masses come from.

The West Siberian lowland, whose height varies from 140 to 250 m, is characterized by winter with little precipitation. At this time of the year, only about 5-20 millimeters falls. What can not be said about the warm season, when 70% of annual precipitation pours onto the earth.

Common in the northern part of the lowlands eternal Frost. The earth freezes to a depth of 600 meters.

Rivers

So, compare the West Siberian Lowland and the Central Siberian Plateau. A strong enough difference will be that the plateau is indented huge amount rec. There are practically no wetlands here. However, there are a lot of rivers on the plain. There are about 2 thousand of them. All of them together bring up to 1200 cubic kilometers of water into the Kara Sea every year. That's an amazing amount. After all, one cubic kilometer contains 1,000,000,000,000 (trillion) liters. most rivers Western Siberia fueled melt waters or summer precipitation. Most of water flows down during the warm season. When a thaw occurs, the level in the rivers can rise by more than 15 meters, and in winter they are ice-bound. Therefore, in cold period stock is only 10%.

The rivers of this part of Siberia are characterized by slow currents. This is due to the flat terrain and slight slopes. For example, the Ob for 3,000 km drops by only 90 m. Because of this, the speed of its flow does not exceed half a meter per second.

lakes

There are even more lakes in these parts than rivers. And many times more. There are about a million of them. But almost all of them are small. A feature of local lakes is that many of them are filled with salt water. They also overflow very strongly in the spring. But over the summer they can significantly decrease in size, and by autumn they can completely disappear. During the last period, thanks to precipitation, the lakes are filled with water again, freeze in winter, and the cycle repeats. This does not happen with all water bodies, but with the so-called “mist” lakes that occupy the territory of this lowland - the West Siberian Plain. It is also characterized by another type of lakes. They occupy the natural unevenness of the relief, various pits and depressions.

swamps

Another feature of Western Siberia is that it beats all records in terms of the number of swamps. It was within the boundaries of this lowland that spilled which are considered one of the largest in the whole the globe. Increased waterlogging is due to the high content of peat in the ground. The substance is able to retain a lot of water, because of this, “dead” areas appear. The area itself also contributes to the formation of swamps. A plain without drops does not allow water to drain, and it remains in a practically immobile state, eroding and softening the soil.

natural areas

Due to the fact that Western Siberia is strongly stretched from north to south, transitions are observed in it. They change from tundra in the north to deserts and semi-deserts in the south. Part of the lowland is occupied by the tundra zone, which is explained by the general northern position of the entire territory of the plain. To the south, the tundra gradually turns into the forest-tundra, and then into the forest-bog zone. The latter occupies 60% of the entire territory of Western Siberia.

There is a rather sharp transition to the steppe regions. Birch is the most common here, as well as aspen. In addition to them, the plowed steppe zone also occupies the extreme southern position in the plain. The West Siberian Lowland, whose geographical position is directly related to the distribution by zones, also creates favorable conditions for pine forest located on low sandy spits.

The region is rich in representatives of the animal world. For example, about 99 species of mammals live here. Among them are fur-bearing animals such as arctic foxes, weasels and sables. There are large predators - bears and lynxes. Also, many birds live in these parts. In the reserves there are peregrine falcons, hawks and golden eagles. There are also birds listed in the Red Book. For example, a black stork or a white-tailed eagle.

Mineral resources

Compare geographic location West Siberian Lowland with any other, and it will become clear that it is in the described plain that about 70% of oil production is concentrated. The plain is also rich in deposits hard coal. The total area of ​​land rich in these resources is estimated at 2 million square meters. km. The timber industry is also well developed. The greatest advantage is given to coal mining in the Kuzbass.

Central Siberian Plateau

Compared to the West Siberian Lowland, the Central Siberian Plateau is not waterlogged due to the fact that it is located on a hill. However river system denser, which is also fed by rains and melting snow. Permafrost is ubiquitous. The climate on the plateau is sharply continental, which is why, as in the West Siberian Lowland, there are large temperature fluctuations in winter. The average in the north reaches -44 o C, and in the south -22 o C. This is also typical for summer period. There is less variety of animals, but bears, reindeer and hares are also found. The plateau, as well as rich in oil and gas deposits. To this are added various ores and

Geological structure of Western Siberia

The basis of the West Siberian Plain is a young plate with by the same name. The plate in the east borders on the Siberian platform, from the south Paleozoic structures of Central Kazakhstan, Altai, the Salair-Sayan region approach it, and in the west the border goes with the folded system of the Urals. Define northern border difficult, because it is covered with water Kara Sea. The basis of the West Siberian Plate is the Paleozoic basement, with an average depth of $7$ km. AT mountainous areas in the southeastern part, ancient Precambrian and Paleozoic rocks come to the surface, and within the West Siberian Plain they are hidden by a thick cover of sedimentary rocks.

The West Siberian plate began its formation in the Mesozoic era, in the Upper Jurassic period. At this time, the area between the Urals and the Siberian platform sank, resulting in a huge sedimentation basin. Marine transgressions captured the West Siberian plate more than once in the course of its development. In the Lower Oligocene, the plate was freed from the sea and turned into a huge lacustrine-alluvial plain. A new uplift of the northern part of the plate occurs in the late Oligocene and Neogene, and in the Quaternary period of the Cenozoic era, the plate sinks again. The development of the plate occurs in a way that resembles the process of oceanization and the development of swamps.

The foundation of the slab is divided into two parts:

1. External instrument belt. It is represented by slopes of mountain-folded framing descending towards the central part of the depression. The foundation is located at a depth of $2.5$ km. In the southwest of the Kustanai saddle, it approaches the surface by only $300$-$400$ m.
2. Inner area. It is divided into two stages: the southern stage is the Sredneobskaya mega-anteclise with a basement depth of up to $4$ km and the northern stage is the Yamal-Taz mega-syneclise lowered to a depth of up to $12$ km.

Between the sedimentary cover and the basement of the plate lies a transitional complex, the age of which is Triassic-Lower Jurassic. The foundation underwent stretching and, as a result, the formation of an inland rift zone with a system of graben-like depressions. The basins were the place of accumulation of sedimentary-volcanic and sedimentary coal-bearing continental sequences up to $5$ km thick. AT transition complex have and igneous rocks represented by basaltic lavas and tuffs.

The development of the intracontinental rift zone within Western Siberia did not lead to the formation of a new ocean. Almost continuous formation of the cover under conditions of plate subsidence took place in the Mesozoic and Cenozoic era. It is composed of sandy-siltstone coastal-continental deposits and marine clayey and sandy-clayey strata. Their thickness reaches $4$ km in the southern part and $7$-$8$ km in the northern part. Numerous local structures are expressed in the sedimentary cover. These are mainly reservoirs of oil and gas.

The general orographic features of Western Siberia were already formed by the end of the Neogene. The sea level was $200$-$250m lower than the modern one, and a significant part of the bottom of the Kara Sea was land. At the end of the Neogene, a general cooling of the climate and the development of the Quaternary glaciation began.

Relief of Western Siberia

The geological development of the territory, tectonic structure and exogenous relief-forming processes had a great influence on the development of the modern relief in Western Siberia. The irregularities of the foundation were leveled as a result of the accumulation of a thick layer of loose deposits. The periphery of the plain has a small amplitude of uplifts, reaching $100$-$150$ m. The central and northern parts of the plain are characterized by subsidence of $100$-$150$ m. Nevertheless, a number of lowlands and uplands can be distinguished. The plain is open to the north, to the Kara Sea, and has the form of a stepped amphitheatre.

There are three altitudinal levels on the territory of the West Siberian Plain:

1. The first level has a height of less than $100$ m and occupies half of the territory;
2. The second level is at an altitude of $100$-$150$ m;
3. The third level is located in the range of $150$-$200$ m with small sections from $250$-$300$ m.

The edges of the plain have more high level and are represented by the North Sosvinskaya, Verkhnetazovskaya, Lower Yenisei Uplands, the Ob plateau, Turinskaya, Ishimskaya, Kulundinskaya, Ketsko-Tymskaya plains. The northern and central parts of the plain are represented by areas below $100$ m. These are the lowest parts of the plain. Less than $50$ m in height are the Nizhneobskaya, Nadymskaya, Purskaya, Tazovskaya, Kondinskaya lowlands. In the inner parts of the plain there is a strip of distinctly pronounced uplands - Verkhnetazovskaya, Numto ridge, Belogorsky mainland, Lyulimvor.

From the orographic point of view, the elevation of the plain along the edges and the lowering of the plate surface towards the center are clearly visible. The interior regions of the plain, where thick Mesozoic deposits occur, are already losing the clarity of expression in the relief of large basement structures. The number of inversion structures is growing. The Vasyugan Plain, for example, is nothing but an anteclise located within the syneclise. Within the inner zone, under the conditions of recent subsidence, the formation of accumulative and reservoir-accumulative plains took place. They are composed of Neogene-Quaternary loose deposits.

The types of morphosculptures created by exogenous relief-forming processes are located on the plain in the direction from north to south. Off the coast of the Kara Sea there are sea plains. They were formed in the postglacial period after the retreat of the sea. Moraine and water-glacial plains are located to the south. Here they are adjoined by glacial, lacustrine-alluvial plains.

Minerals of Western Siberia

The main wealth of the West Siberian Plain is hydrocarbons - oil and gas. Experts estimate the area of ​​promising oil and gas fields at $1.7 million sq. km. Such large deposits as Samotlor, Megion, located in the Nizhnevartovsk region. Large deposits in the Surgut region are Ust-Balykskoye, Fedorovskoye, etc.

Natural gas in the Subpolar region - the field Medvezhye, Urengoy, in the Arctic - Yamburgskoye, Ivankovskoye, etc. There is oil and gas in the Urals, and new promising fields have been discovered on the Yamal Peninsula. In general, more than $300$ of oil and gas fields have been discovered on the plain.

In addition to hydrocarbons, large deposits are known in Western Siberia hard coal, the main reserves of which are located within the Kuzbass. Kuznetsk coal reserves are estimated at $600 billion tons. Almost $30$% of these coals are coking. The large thickness of coal seams and their proximity to the surface allow them to be developed not only by mines, but also open way. Brown Kansk-Achinsk coals occur to the northeast of the Kuznetsk basin. In the largest Itatskoye field, the thickness of the seams reaches $80$ meters, and the depth of occurrence is from $10$ to $220$ meters. The cheapest coal in Russia is mined here. Anthracite coals are concentrated in the Gorlovsky basin, located in the south Novosibirsk region. brown coals Tyumen region not put into operation yet.

From fuel resources in the depths of the West Siberian Plain is $50$% of all-Russian reserves peat.

Stands out for its reserves and ore base. Significant Resources iron ore are concentrated in the Narymskoye, Kolpashevskoye, Yuzhno-Kolpashevskoye deposits. Brown ironstones lie here. Mountain Shoria is characterized by deposits of magnesium ores - these are Tashtagol, Sheregesh. In Altai - Inskoye, Beloretskoye deposits. There are deposits of manganese ores, nephelines in Kemerovo region. Place of Birth mercury in Altai.

The lakes of the Kulunda steppe contain reserves soda and salt.

Limestones in the Novosibirsk and Kemerovo regions.

Altai has significant reserves building materials.

In addition to minerals, Western Siberia is rich in forest resources . Timber stocks make up $11$% of Russian stocks.

Remark 1

Issues of protection and rational use natural resources are also relevant for Western Siberia. The thoughtless use of resources can ruin the environment and lead to negative consequences.

Peculiarities geographical location Western Siberia

Remark 1

To the east of the Ural Mountains lie vast expanses of the Asian part of Russia. This territory has long been called Siberia. But due to the diversity of the tectonic structure, this territory was divided into several individual regions. One of them is Western Siberia.

The basis of Western Siberia is the West Siberian Plain. It's bounded in the west Ural mountains, and in the east - the Yenisei River. In the north, the plain is washed by the waters of the seas of the Arctic Ocean. Southern borders approach the Kazakh uplands and the Turgai plateau. The total area of ​​the plain is about $3$ million km$²$.

The characteristic features of the West Siberian Plain are the following features:

• insignificant fluctuation of heights in such a vast territory;
• the length from north to south and an almost flat relief led to a clear change in natural zones with latitude (classical latitudinal zonality);
• formation largest areas swamps in the taiga and landscapes of salt accumulation in the steppe zone;
• a transitional climate is formed from the temperate continental of the Russian Plain to the sharply continental of Central Siberia.

The history of the formation of the plain

The West Siberian Lowland lies on the Upper Paleozoic Plate. Sometimes this tectonic structure also called epihercynian. The crystalline basement of the slab contains metamorphosed rocks. The foundation sinks towards the center of the slab. The total thickness of the sedimentary cover exceeds $4$ km (up to $6-7$ km in some areas).

As already mentioned, the foundation of the slab was formed as a result of the Hercynian orogeny. Further there was a peneplenization (leveling of a relief by means of erosive processes) of the ancient mountainous country. In the Paleozoic and Mesozoic, troughs form in the center, and the foundation was flooded by the sea. Therefore, it is covered with a significant thickness of Mesozoic deposits.

Later, during the era of the Caledonian folding, southeastern part the plains rose from the bottom of the sea. In the Triassic and Jurassic, the processes of relief denudation and the formation of a sedimentary rock mass predominated. Sedimentation continued into the Cenozoic. In the era ice age the north of the plain was under the thickness of the glacier. After its melting, a significant area of ​​Western Siberia was covered with moraine deposits.

Characteristics of the relief of Western Siberia

As already noted, geological history led to the formation of a flat relief on the territory of the West Siberian Plain. But more detailed study The physical and geographical features of the region showed that the orography of the territory is complex and diverse.

Large relief elements on the territory of the plain are:

• lowlands;
• sloping plains;
• hills;
• plateau.

In general, the West Siberian Plain has the form of an amphitheater, open to the North Arctic Ocean. Plateau and upland areas predominate in the western, southern and eastern periphery. AT central regions and lowlands prevail in the north. The lowlands are represented by:

• Kandinsky;
• Nizhneobskaya;
• Nadymskaya;
• Purskoy.

Among the plateau, the Ob plateau stands out. And the elevations are presented:

• Severo-Sosvinskaya;
• Turin;
• Ishimskaya;
• Chulym-Yenisei and others.

In the relief, there are zones of glacial-marine and permafrost-solifluction processes (tundra and northern taiga), fluvioglacial forms of lacustrine-glacial plains (up to the middle taiga), and a zone of semiarid structural-denudation plateaus with erosion processes.

Remark 2

Currently, human economic activity plays an important relief-forming role. The development of Western Siberia is accompanied by the development of minerals. This causes changes in the structure of the layers rocks and changes the course of physical and geographical processes. erosion processes are intensifying. In the south during development Agriculture is applied to the soil a large number of minerals. Chemical erosion develops. It is necessary to take a balanced approach to the development of the nature of Siberia.

Features of the geographical position of Western Siberia

Remark 1

To the east of the Ural Mountains lie vast expanses of the Asian part of Russia. This territory has long been called Siberia. But due to the diversity of the tectonic structure, this territory was divided into several separate regions. One of them is Western Siberia.

The basis of Western Siberia is the West Siberian Plain. It is bounded in the west by the Ural Mountains, and in the east by the Yenisei River. In the north, the plain is washed by the waters of the seas of the Arctic Ocean. The southern borders approach the Kazakh uplands and the Turgai plateau. The total area of ​​the plain is about $3$ million km$²$.

The characteristic features of the West Siberian Plain are the following features:

• insignificant fluctuation of heights in such a vast territory;
• the length from north to south and an almost flat relief led to a clear change in natural zones with latitude (classical latitudinal zonality);
• formation of the largest swamp areas in the taiga and salt accumulation landscapes in the steppe zone;
• a transitional climate is formed from the temperate continental of the Russian Plain to the sharply continental of Central Siberia.

The history of the formation of the plain

The West Siberian Lowland lies on the Upper Paleozoic Plate. Sometimes this tectonic structure is also called epihercynian. The crystalline basement of the slab contains metamorphosed rocks. The foundation sinks towards the center of the slab. The total thickness of the sedimentary cover exceeds $4$ km (up to $6-7$ km in some areas).

As already mentioned, the foundation of the slab was formed as a result of the Hercynian orogeny. Further there was a peneplenization (leveling of a relief by means of erosive processes) of the ancient mountainous country. In the Paleozoic and Mesozoic, troughs form in the center, and the foundation was flooded by the sea. Therefore, it is covered with a significant thickness of Mesozoic deposits.

Later, during the era of the Caledonian folding, the southeastern part of the plain rose from the bottom of the sea. In the Triassic and Jurassic, the processes of relief denudation and the formation of a sedimentary rock mass predominated. Sedimentation continued into the Cenozoic. During the Ice Age, the north of the plain was under the thickness of the glacier. After its melting, a significant area of ​​Western Siberia was covered with moraine deposits.

Characteristics of the relief of Western Siberia

As already noted, the geological history determined the formation of a flat relief on the territory of the West Siberian Plain. But a more detailed study of the physical and geographical features of the region showed that the orography of the territory is complex and diverse.

Large relief elements on the territory of the plain are:

• lowlands;
• sloping plains;
• hills;
• plateau.

In general, the West Siberian Plain has the form of an amphitheater, open to the Arctic Ocean. Plateau and upland areas predominate in the western, southern and eastern periphery. Lowlands prevail in the central regions and in the north. The lowlands are represented by:

• Kandinsky;
• Nizhneobskaya;
• Nadymskaya;
• Purskoy.

Among the plateau, the Ob plateau stands out. And the elevations are presented:

• Severo-Sosvinskaya;
• Turin;
• Ishimskaya;
• Chulym-Yenisei and others.

In the relief, there are zones of glacial-marine and permafrost-solifluction processes (tundra and northern taiga), fluvioglacial forms of lacustrine-glacial plains (up to the middle taiga), and a zone of semiarid structural-denudation plateaus with erosion processes.

Remark 2

Currently, human economic activity plays an important relief-forming role. The development of Western Siberia is accompanied by the development of minerals. This causes changes in the structure of rock layers and changes the course of physical and geographical processes. erosion processes are intensifying. In the south, during the development of agriculture, a large amount of minerals is introduced into the soil. Chemical erosion develops. It is necessary to take a balanced approach to the development of the nature of Siberia.